Indicator for rubber mixers or the like



ug. l0, 1948. D. w. Macu-:OD ET AL 2,445,657

INDICATOR FOR RUBBER MIXERS OR LIKE Filed sept. 2e, 1947v 2 sheets-sheet 1 D w MacLEoD Er Al. 2,446,657

INDICATOR FOR RUBBER MIXERS OF. THE LIKE Aug. 10, 194s.

Flled Sept 26 1947 Patented ug. 10, 1948 INDICATOR FOR RUBBER MIXERS R THE LIKE Douglas W. MacLeod, Ansona, and Raymond H.

Perkins, Milford, Conn., assignors to Farrel- Birmingham Company, Inc., Ansona, Conn., a corporation of Connecticut Application September 26, 1947, Serial No. 776,182

7 Claims. l

This invention relates to indicators for pistons or plungers, and more particularly to a device which will indicate the position oi the piston or plunger of a machine, such as a rubber masticator, for example.

In machines where there is employed a piston or plunger operated b-y fluid pressure, it is very often desirable for the operator to know the position of the plunger at any time. As the plunger is operated by uid pressure, the cylinder within which the piston or plunger operates musi-be made oi material which will withstand the pressure which it is necessary to employ, and, for this reason, it is often impossible to make the cylinder of transparent material. It is, therefore, impossible for the operator to know the position of the plunger, and it is many times impracticable to arrange for a part of the plunger or an indicator on the plunger to project through the cylinder orother part of the device to give an indication of its position.

It is contemplated by the present invention to indicate the position of the piston or plunger magnetically, and to eiect this result the piston is made of non-magnetic material, and a permanent magnet is attached to, or incorporated in, the piston, which magnet is of sulcient strength to act through the wall of the cylinder upon a follower or the like disposed at the outside of the cylinder.

.As shown in the present application, the cylinder is also made of non-.magnetic material, and upon the outer wall of this cylinder is secured a transparent tube extending longitudinally of the cylinder. Within this tube is disposed a freely slidable follower of magnetic material of light weight, so that it will be attracted by the magnet and move along the tube with the piston, thus indicating the position of the latter at all times to the operator of the machine.

Although capable of other application, the indicating device is shown in the present instance as being applied to the plunger or piston of a rubber masticator. A machine of this character is provided with a chamber within Which the masticator rotors are mounted, and a charging stack is positioned above the chamber through which the material to be acted upon by the rotors is fed into the chamber. Slidably mounted in thischarging stack is a weight or closure member designed to be moved upwardly to a position to permit the charging of the material into the chamber, and, after the latter has been charged, to be moved downwardly to maintain pressure upon the charge while it is being acted upon by the rotors. To this weight is secured a plunger which extends into a cylinder mounted above the charging stack and a piston is secured to the plunger Within the cylinder, so that the plunger and weight may be operated by iluid pressure ad# mitted to the cylinder in order that the 'weight may be held downwardly upon the charge under pressure. The indicator is mounted upon the outside of the cylinder and larranged to be moved by a magnet which is, in `this instance, mounted in the piston itself.

One object of the present invention is to lprovide a mechanically-operated piston or plunger with an indicator which will indicate the position of the piston upon the outside of the cylinder within which the piston moves.

A still further object of the invention is to provide a machine, such as a rubber masticator, for example, with an indicator to indicate the position of the plunger or weight in the charging stack, the indicator being positioned without the cylinder within which the plunger-operating pis#` ton is mounted, and being arranged to be operated by movements of the piston.

To these and other ends the invention consists inthe novel features and combinations of parts to be hereinafter described and claimed.

In the accompanying drawings: l

Fig. 1 is a sectional view of a rubber masticator embodying our invention;

Fig. 2 is an enlarged sectional view oi the upper portion of the charging stack and cylinder mount--v ed thereon showing the yplunger in its raised position;

Fig. 3 is a. fragmentary iront elevational view of the upper portion of the charging stack, some parts being broken away for the sake of clear--v ness;

Fig. 4 is a partial sectional View on line 4--4 of Fig. 1; and

Fig. 5 is a partial vertical sectional View through the piston. Y To illustrate a preferred embodiment of our invention, we have shown in Fig. 1 of the drawings a machine, such as a rubber mixeror masti-Y cator, the machine embodying a double cylindrical chamber l0 within which are mounted bladed rotors I I and I2 which cooperate in a well-known way to mix, masticate, and reduce to plastic form, a charge of rubber'or other material which may be introduced into the chamber. It will be understood that, while a double rotor machineis shown, our improvements may be employed in connection with a rubber masticator having -a closure member I6, this weight being adaptedig during the operation of the device,vto Yrest uponV the charge within the chamber and-'exert.pures-v sure thereon. It, of course, also acts to forceA into the chamber the material. introduced intoY the charging stack through the opening. ,-I4..

Mounted above the chargingfstack is,.a^cy;linder1 Il, and the plunger or piston rod I5 extends inter. if

this cylinder, and secured to its. upper ,end is the` piston I8 slidably mounted withinlthe cylinder.

The lower end of the cylinder is closed.';by,.,-t;heY

head I9, and the piston rod passes through a packing gland securedinthehead I9 andalso. through:` agland .al secured in .-.a i portion of the.

` upper endofthe stack;

The. r upper end of the cylinder .is closed. by the head-22, and-.pressure fluid is introduced above andfbelowthe piston I8 t-hroughlthe lines 23 and 24f,.y1.hich .lead froma suitable .valve 425 controlling the introduction of. fluidV pressure into one or the other of .the lines-23 and` 24 .from the line. 2 6 f leading toasource of supply. -It will, of course, beobvious that, when pressure uidisintroduced to they-line 23. below the. piston,V thegweig'nt IE .will befcausedto rise, and, whenrluid pressure isintrocluced.V intox the. cylinder 1 through.. the line ..24 above. the piston, the weight will be caused to de.- scend and exert pressure onine-charge. in the usual manner.-

The yupper and lower. positionspf. the Weight- I I5. are determinedfby the-upper .andflowerheads-oi the-..cyli nder, and this weightmay be held in its upper` position, asshowninsligfs, by a stop. 28. mounted. in thewall: ofthe stack-.andfmanipulatedfto or fromengagement with the weight by the handle 29. Y

In. order tov provide: indicating means-upon. the outside.A of .the cylinder I1,- the piston I8 .is-composed of nonfmagnetic.material, .such as` brass, for example, andin a recess 3.l..adjacent the. perphery of. the. piston is. mounted. a permanent magnet 32 of some materialwhichcan.bestrongly. .,magnetized, such, for example. asthemetal a1nico.. Asshown, this. magnet/is ofsemi-cylindrical;.form,.so as .to.present. two, poles at the exterior of the piston adjacent the wall.A olfgiie cylinder. Themagnet-may beheld. inzplace by solder or thelike 33.

The cylinder wall is alsomade of .nonfmagnetie material, preferably some type of non-magnetic metal, as it must. be sufliciently strong... to withstand the high pressure of the pressure luidjused therein.. Secured upon .theoutside of thecylinder byclips or the' like 34-is a tube 35 ofv transparent material, such as transparent plastic, for Vexample, the upper and lower ends of this tube belng#l closed byA plugs 36'.- v Within this tube is mounted aA follower 31"-of magnetic material, this followewbeing., as shown, Yinfthe form of. a' hollow semi-cylindrical body-,1 sogthat it will-slideffreely upwardly -and downwardly 'in` thetube35 and, at the-.Sametime befof relatively'light zweight, so that it. will be attracted by them'agnet :.32aand-fbe carried withthe movements: ofthe; piston. .It will be apparent that, as thez pistQm-movesfwithin the cylinder" .1I 1, the indicator 3 .'I will also moye within -th'ev tube- ,35. andwll. at, oncefzindicate; to. the

operator through the transparent tube the position of the piston and, therefore, the position of the weight I6,

In the case of some operations, such as the mastication of rubber, for example, the chamber may be chargedwith lumps ofrubberwhich, when the operation isrst begun, will-remainin the charging stack I3. During the operation of the machine, the level of the charge will rise and fall to a considerable extent under the pressure of the rotorbladesand cause the Weight to reciprocate wit-hin the stack. The amount of these oscillationsor'reeiprocations will be indicated by the follower-31. ,Whem however, the charge is re- :sduceditmplastic form, it will be contained wholly or-.largelyfwithin` the chamber IIJ, and the weight I I .will b eJnoved to its lower position which will also be indicated bythe follower. Thus the actiornof. the follower will indicate to the operator the condition of the mass being treated Within the chamber.

Whilewehave shown and described a preferred embodiment `of our invention, it will be Aunder-- stood.. that it is not to be limitedto all vof theidef. tails shown, but is capable of modication. and. variation within the spirit of the invention and within the scopeof vthe claims,

What we claim is:

l. In. a mixing or masticating machine, a chamber .having anopening, a cylindersupported above the chamber, a piston. inthe cylinder, a. weight connected to the piston and adaptedto extend into said openingy .a magnet carriedY by the piston and having,l pole portions-substantially iiush with the outer surface thereof, and a follower of magnetic material disposed at the cutside ,of the cylinder and adapted to bemoved therealong by said magnet.

2. In a devceof the class described, achem-` ber, a cylinder, a pressure-fluid,operated.pistony therein, a plunger connected to the; piston and extendingV toward the chamber,.means..toindicate the. position .of thepiston in the cylinder comprising a magnet carried by. the. pistonand. having poleportions substantially flush withthe outer surface thereof, .a follower disposed on the outside ofthe cylinder wall and adapted to'be. moved by saidymagnet, and -a guide tube on the. cylinder. within `which the follower is mounted.V

3. In a device of the class described, a machine, hayinga piston-operated member and .including a cylinder andv apiston therein connected to. said. member, means .to indicate4 thev position of the,A piston comprisingv a magnet embedded. in the, piston and .exposed at the lateral f-ace'of the pistonadjacent the innersurface of the cylinder. wal1,.a guide member on the outside of the cylin, deri wall. and extending.v longitudinallythereof, anda followerfreely movable in said guidememf ber and adapted to be moved bysaid magnet .as the pistonis moved.

4. A machine for treating plastic material comprising. a chamber, a pistonrod .extending into the chamber, anelement onsaid rod exert.-` ing pressure on the. material in the chamber, a piston connected to said rod, a cylinderwithin which said piston operates, means-for introducing iluidpressure into. the. cylinder, a magnet. embedded in the piston and having. )pole portions, exposedatthe lateral face. of the piston, .and afollowerof. magnetic ,material `slidably mounted. ontheoutside ofthe. cylinderand adapted.. to be. moved. by. the magnet.

5. vA krubber. masticating machine,v comprising. a chamber, .a charging.- stack communicating..

with the chamber, a Weight slidably mounted in said stack, a cylinder supported upon the stack, a piston within the cylinder connected tu said weight to move the same, means for introducing fluid pressure into the cylinder to move the piston, a permanent magnet; embedded in the piston and having opposite pole portions exposed at the lateral face of the piston, an indicating means mounted upon the outside of the cylinder, said means comprising a follower of magnetic material adapted to be moved by said magnet, and guide means to maintain said follower against the cylinder wall.

6. A rubber masticating machine comprising a chamber, a charging stack communicating with the chamber, a weight slidably mounted in said stack, a cylinder supported upon the stack, a piston within the cylinder connected to said weight to move the same, means for introducing uid pressure into the cylinder to move the piston, a permanent magnet embedded in the piston and exposed at the lateral surface thereof, an indicating means mounted upon the outside of the cylinder, said mean-s comprising a follower of magnetic material adapted to be moved by said magnet, and guide means to maintain said follower against the cylinder wall, said guide means comprising a tubular member of transparent material within which the follower is mounted.

7. A rubber mastlcating machine comprising a chamber, a charging stack communicating with the chamber, a weight slidably mounted in said stack, a cylinder supported upon the stack, a piston within the cylinder yconnected to said weight to move the same, means for introducing iiuid pressure into the cylinder to move the piston, a permanent magnet carried by the piston, an indicating means mounted upon the outside of the cylinder, said means comprising a follower of magnetic material adapted to be moved by said magnet, and guide means to maintain said follower against the cylinder wall, said follower comprising an element of hollow semi-cylindrical form, and said magnet being of semi-cylindrical form and presenting opposite poles substantially flush with the lateral surface of the piston.

DOUGLAS W. MACLEOD. RAYMOND H. PERKINS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 957,082 Nash May 3, 1910 1,216,261 Ashley Feb. 20, 1917 1,279,824 Banbury Sept. 24, 1918 

